With the new perspective on potential uses of a 'noop'
enumerator (or whatever we decide to call it) there is
no longer a need to provide for any extra 'user' space
in the stack header structures used by slab & meminfo.
Signed-off-by: Jim Warner <james.warner@comcast.net>
In addition to that text shown below the line which is
common to several commit messages, this patch contains
several minor changes with lessor impact upon the API:
. A 'read' was added to function procps_slabnode_count
(but only when necessary, i.e. info->nodes_used == 0).
. The #include header files are ordered alphabetically
now, with all those <sys/??> types separately grouped.
------------------------------------------------------
. The former 'chains' have now become 'stacks' without
the 'next' pointer in each result struct. The pointers
initially seemed to offer some flexibility with memory
allocations and benefits for the library access logic.
However, user access was always via displacement and a
a statically allocated chain was cumbersome to define.
. An enumerator ending in '_noop' will no longer serve
as a fencepost delimiter. Rather, it has become a much
more important and flexible user oriented tool. Adding
one or more such 'items' in any items list passed into
the library becomes the means of extending the 'stack'
to also include user (not just library) data. Any such
data is guaranteed to never be altered by the library.
. Anticipating PID support, where many different types
must be represented in a result structure, we'll adopt
a common naming standard. And, while not every results
structure currently needs to reflect disparate types a
union will be employed so the same dot qualifier ('.')
can be used consistently when accessing all such data.
Signed-off-by: Jim Warner <james.warner@comcast.net>
With this patch, we will be close to an implementation
which will be needed when accommodating tasks/threads.
The following explanation was from an earlier message:
The slabtop requirements are similar to those of PIDs.
One must accommodate the variable number of slab nodes
(PIDs) while also accepting different data (char * and
unsigned long). Furthermore, some generalized means to
sort all that acquired stuff must somehow be provided.
------------------------------------------------------
So this patch expands the API to provide dynamic chain
allocation plus allow sorting of those dynamic chains.
While specific to slab needs (nodes, not global stats)
it is not too early to begin to think of newlib chains
as the opaque replacement for a deprecated old proc_t.
Better yet, any newlib chain is inherently variable in
length, something the old proc_t couldn't claim to be.
Of course, as we get to PIDs we'll want to grow/shrink
chains (easily accomplished with a special item enum).
And we'll want to grow/shrink those **head arrays too.
But these minor details don't seem insurmountable now.
Signed-off-by: Jim Warner <james.warner@comcast.net>
This was Craig's original patch, referenced below, but
it was never pushed to newlib. It has now been rebased
on top of some diskstat stuff to serve as a beginning.
The original effort was perfectly serviceable (after a
memory leak was fixed) but the approach would not have
served future PID needs when that proc_t went bye bye.
The slabtop requirements are similar to those of PIDs.
One must accommodate the variable number of slab nodes
(PIDs) while also accepting different data (char * and
unsigned long). Furthermore, some generalized means to
sort all that acquired stuff must somehow be provided.
So I wanted to try a different approach that seemed to
hold potential for satisfying future top and ps needs.
Subsequent commits will make that attempt, building on
Craig's original patch whose commit msg appears below.
------------------------------------------------------
All of the /proc/slabinfo related calls have been changed
here. They follow the same procps_slabinfo_* format.
Made both the slabtop and vmstat programs use the new
API as one was using the old one and one was just sort
of trying to do its own thing.
Sorting of slabnodes is also possible via the library.
Reference(s):
http://www.freelists.org/post/procps/Sorting-slabsprocesses,3http://www.freelists.org/post/procps/library-rework-slabinfo-calls
Signed-off-by: Craig Small <csmall@enc.com.au>
Signed-off-by: Jim Warner <james.warner@comcast.net>
There soon will be slab types per cgroup meaning the name of the slab
will have the cgroup name in parathensis after the slab name. This
minor change increases the slab name size to cater for this.
Signed-off-by: Craig Small <csmall@enc.com.au>
